<I>Ascidiella aspersa</I>, a sea squirt
Eggs from Ciona intestinalis
Elongation of the ascidian embryo
(a series of images taken from a recording made over approximately 6 hours)
Sperm and eggs are readily isolated from the adult hermaphrodite (video 1 below). Upon mixing the gametes together embryogenesis can be followed through fertilization (video 2), cleavage (video 3) and morphogenesis (above) to hatching of the larva (video 4). The eggs are 200 microns in diameter. Sea squirt development was first studied at Dale by Elena Ambrosio, Caroline Coleman, Desiree Douglas, Rachel Hignet and Kathryn Porges in Sep.'95. Compare the Ascidiella aspersa eggs to those of two other sea squirt species, Ascidiella scabra (video 5) and Ciona intestinalis (still images below).